Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

2.4K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.4K
Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

1.9K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
1.9K
Regioselectivity of Electrophilic Additions-Peroxide Effect02:35

Regioselectivity of Electrophilic Additions-Peroxide Effect

8.7K
In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
8.7K
Aromatic Hydrocarbon Cations: Structural Overview01:18

Aromatic Hydrocarbon Cations: Structural Overview

2.8K
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group...
2.8K
Electrochemistry: Overview01:04

Electrochemistry: Overview

2.1K
Electrochemistry is the branch of chemistry that studies the relationship between electrical quantities and chemical reactions, particularly oxidation and reduction. Oxidation is the loss of electrons from a substance, whereas reduction refers to the gain of electrons. A substance with a strong electron affinity is called an oxidizing agent (oxidant), and a reducing agent (reductant) is a species that donates electrons. Oxidation and reduction processes are pivotal to electrochemical reactions,...
2.1K
Aromatic Hydrocarbon Anions: Structural Overview01:18

Aromatic Hydrocarbon Anions: Structural Overview

2.8K
Neutral hydrocarbons like cyclopentadiene with an odd number of carbon atoms and one intervening CH2 group in the ring are not aromatic. Cyclopentadiene with 4 π electrons does not satisfy the 4n + 2 π electron rule. Additionally, the intervening CH2 group is sp3 hybridized and lacks a vacant p orbital, thereby interrupting the overlap of p orbitals in a continuous manner and preventing the delocalization of π electrons throughout the ring.
Due to the absence of continuous...
2.8K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Plasmodesmata display dynamic local and systemic redox responses during plant stress.

The Plant cell·2026
Same author

Reversible Ring Oxidation of a β-β Linked 24π Antiaromatic Sapphyrin to a 22π Aromatic Dication Dimer.

Organic letters·2025
Same author

Steric hindrance modulated efficient thermally activated delayed fluorescence with non-linear optical, ferroelectric and piezoelectric properties.

Chemical science·2025
Same author

Reversible Ring Oxidation of 48π Planar Nonaphyrins to Open Shell 46π Dications.

Chemistry (Weinheim an der Bergstrasse, Germany)·2025
Same author

Thieno[3,2-b]thiophene Incorporated Redox Active 22π and 34π Core-Modified Expanded Isophlorinoids.

Chemistry (Weinheim an der Bergstrasse, Germany)·2024
Same author

Facile synthesis and characterization of aza-bridged all-benzenoid quinoidal figure-eight and cage molecules.

Chemical science·2024

相关实验视频

Updated: Jul 17, 2025

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
11:44

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Published on: October 18, 2018

26.6K

在电化学活性核修饰的扩展型氨酸体的拓多样性.

Hosahalli S Udaya1, Vishnu Mishra1, Tullimilli Y Gopalakrishna1

  • 1Department of Chemistry, Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India.

Organic letters
|September 5, 2023
PubMed
概括

基于烯的扩展烯酸随着添加更多的烯单位而扭曲. 八氨酸在溶液中表现出形状变化,但在固态中是刚性的,更大的系统表现出独特的电子性质.

科学领域:

  • 有机化学 有机化学
  • 超分子化学 超分子化学
  • 材料科学 材料科学 材料科学

背景情况:

  • 扩展型氨酸是具有可调节电子和光物理性质的宏环化合物.
  • 提奥芬的结合影响了这些宏观循环的形状灵活性和电子结构.

研究的目的:

  • 为了研究基于烯的扩大烯酸的结构变化,增加了越来越多的烯酸单位.
  • 描述较大的硫基氨酸的电子性质和氧化还原行为.

主要方法:

  • 合成和表征基于蒂奥芬的扩展型氨酸.
  • 可变温度NMR光谱学用于研究形状动力学.
  • 谱电化学测量以探测氧化还原特性.

主要成果:

  • 观察到从平面到扭曲形状的过渡随着提奥芬单位的增加.
  • 八素 (40π电子) 在溶液中表现出取决于温度的形状交换,与其刚性固态结构不同.
  • 60π-dodecaphyrin和70π-tetradecaphyrin表现出易于,可逆的两电子氧化与不稳定的激素阴离子中间体.

结论:

  • 构造灵活性是基于硫的扩展型氨酸的关键特征,受π电子数量和结合的影响.

更多相关视频

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation
08:41

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation

Published on: October 10, 2018

24.9K
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
07:12

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

6.3K

相关实验视频

Last Updated: Jul 17, 2025

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
11:44

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Published on: October 18, 2018

26.6K
Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation
08:41

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation

Published on: October 10, 2018

24.9K
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
07:12

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

6.3K
  • 这些系统为需要动态分子架构和可调整的氧化还原特性的应用提供了潜力.